The Enenra are creatures of smoke and vapor who possess a shapeless form in the Mortal Kombat universe. They are at times created from the souls of slain mortals, and can return to their physical forms.
Tomas Vrbada was kidnapped when he was a child by an obscure cult who intended to sacrifice him to a demon. As he was immolated, he'd changed into an Enenra and killed his kidnappers. After killing the members of the cult, he returned to his mortal form but suffered from amnesia and was unaware of the incident. Some time later he'd joined the Lin Kuei and had taken on the codename Smoke.In Smoke's MK 2011 ending, after defeating Shao Kahn, he regains his memory, and remembers his past life as well as the origin of his powers.
The Enenra are creatures that consist of smoke. Enenra can merge with people. Enenra's ability to turn into smoke makes them an extremely dangerous adversary. That is why the clan of Lin Kuei enlisted Smoke, who became Enenra after a mystical ritual, believing that such a "talent" is useful in many tasks.
Since the Enenra are creatures consisting of smoke, all of Smoke's techniques are somehow connected with smoke. For example, he can teleport himself or the enemy with smoke or even become invisible.
The only famous Enenra is Smoke.
In Japanese mythology, Enenra are also present. Unlike the game, they look like a veil of smoke with a human face, and are not at all like the monster from Smoke's ending in the MK (2011). Enenra appear from the fires, and only those who are pure in heart can see them.